mtd: nand: remove nand size print from nand_init function

Add nand_size() function to move the nand size print into initr_nand().
Remove nand size print from nand_init() to allow other function to call
nand_init() without printing nand size.

Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
Reviewed-by: York Sun <york.sun@nxp.com>

common/board_r.c

@@ -426,6 +426,7 @@ static int initr_nand(void)
 {
 	puts("NAND:  ");
 	nand_init();
+	printf("%lu MiB\n", nand_size() / 1024);
 	return 0;
 }
 #endif